Chapter V – Substantive examination of opposition
The same substantive requirements apply in the opposition procedure regarding patentability pursuant to Art. 52 to Art. 57 as in the examination procedure. G‑I to G-VII will therefore also be applied in opposition proceedings. However, it will be more common in opposition proceedings than in examination procedure for the examination as to patentability to be based on the state of the art as made available to the public not by written description but "by means of an oral description, by use, or in any other way" (see Art. 54(2) and G‑IV, 7).